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  • Hey all, just changed over the backend after 15 years I figured time to give it a bit of an update, its probably gonna be a bit weird for most of you and i am sure there is a few bugs to work out but it should kinda work the same as before... hopefully :)

1080p playback on PS3: MPEG2 better than H.264?

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jbeale

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The only device I have that can play 1080p at 30 fps* in real time is a PS3. As a test, I tried rendering the same 6-second sequence in AVC (H.264) and MPEG2 format, both at 50 Mbps. They both look decent in the high-contrast areas, but in the background where there is a smooth gradient, the H.264 shows some blockyness, that the MPEG2 (and the original) does not show. At this bitrate with this clip, the MPEG2 is a clear winner to my eyes. If you have a PS3 or other capable hardware and want to try yourself:

MPEG2: http://www.bealecorner.org/red/test-080108/video/Glass50.mpg
MPEG4: http://www.bealecorner.org/red/test-080108/video/Glass50.mp4
both clips: 1080p, 30 fps, 50 Mbps

Note: the files are not the same size because they both have (silent) audio tracks, but at different audio bitrates.

*You may ask, why not use 24 fps? Because as far as I can tell, the PS3 combined with my HDTV is fixed at 29.97 fps refresh rate, and 24 fps motion does not look right. It's not just the lower frame rate, it is the uneven syncopated judder (looks like a slight, rapid, slowdown/speedup) which I'm pretty sure is the 2:3 pulldown. I never realized that I could see it so easily, but it's pretty apparent, and pretty annoying to me when watching motion that is supposed to be smooth, at 24 fps. Therefore the test clips above are 30 fps, and I don't see this effect at all.

For comparison here is a 1k, 24 fps version (from a different take):
http://www.bealecorner.org/red/test-080108/mp4/Bowl-spin-19-1k.mp4

(If you're lucky enough to have a true 24 fps display, this issue probably doesn't affect you.)
 
jbeale said:
As a test, I tried rendering the same 6-second sequence in AVC (H.264) and MPEG2 format, both at 50 Mbps. They both look decent in the high-contrast areas, but in the background where there is a smooth gradient, the H.264 shows some blockyness, that the MPEG2 (and the original) does not show. At this bitrate with this clip, the MPEG2 is a clear winner to my eyes.
Click to expand...

That is interesting, because according to several studies H.264 should have better quality than MPEG-2 at the same bitrate. Did you turn on the deblocking filter?
 
Yes, I turned on the deblocking filter (it was a lot worse without it).

By the way, I loaded these files back in to Vegas 8 which I used to generate them, and exported full-resolution still frames from the H.264 and MPEG2 files, and I did not see the problems I saw in the PS3 display. So I suspect there may be some quality problems with the PS3 implementation of H.264 decoding. I'd be curious to hear what other people see, if anyone wants to compare them on their hardware.
 
I just watched all 3 videos on my PS3 connected to a Sanyo z2000 1080p projector.

None of the 3 files had any visible blockyness in the background. I used an HDMI connection with the following settings on the PS3.

RGB Full range (HDMI) - Full
Y Pb/Cb Pr/Cr Super-White (HDMI) - On

How did you turn the deblocking filter ON? this setting is only activated during DVD playback?? FW2.10


EDIT: The 24fps video was playing very smoothly! That was a surprise because on my Eizo monitor it wasn't as much...
 
Thank you very much for checking it out Miltos. I am glad to hear it works for you- I wonder why my setup is different. I am using HDMI from PS3 to a Vizio VX37L. I don't think it can be my TV because then the MPEG2 would look bad also.

The deblocking filter I'm talking about was a selectable option during the encoding step (in Vegas Pro 8b).
 
Blue Ray is MPeg 4 (h.264).
 
David Birdy said:
Blue Ray is MPeg 4 (h.264).
Click to expand...

Mpeg-4 has two parts, one is the MPEG-4 Part 2 (I believe), which is regular DCT based, and the joint ITU and JVC MPEG-4 Part 10, which is H.264, which uses a transform slightly different than, though derived from DCT. A good property of H.264 transform vs. MPEG-4 Part 2 DCT transform is that the H.264 is integer based and fully invertible without any data loss, where as DCT inversion is lossy. There are other differences between part 2 and part 10 also.

I believe both Blue ray and HD-DVD were internally H.264 based. The differences were perhaps more in other outward parameters and packaging.
 
Miltos Pilalitos said:
...at least let me tell you that it was one of the best damn clips i have seen on my home theater until now. As good as or maybe better than BluRay.
Click to expand...

Wow! Thank you very much for the feedback. I shot it because I like shiny glass things, the camera really picks up a lot of detail.

According to the Blu-Ray FAQ, http://www.blu-ray.com/faq/ Blu-Ray discs can use any of MPEG2, AVC H.264 or VC-1 codecs at various bitrates. I'm sure many of the available discs are excellent, but of course not everyone starts with source material as clean as the Red can generate, and I doubt they use a 50 Mbps average bitrate if it's a full length feature with extras etc. In fact, the FAQ says the maximum bitrate for Blu-Ray is 40 Mbps.

I was playing the clips from the PS3 internal hard drive, which of course doesn't have a problem with that bitrate.
 
Hi Jbeale,

Interesting footage. My old PPC-based Mac-lap top was struggling to play it, hence I have to see individual frames. Seems very nice. Thanks for sharing.

One comment on internet-based files that are so big: Your file is mp4 (MPEG-4 container) and the comment applies to Quicktime files also. Kindly place the resource atom before data atom in Quicktime and MPEG-4 files, so that they can be directly viewable on the internet before waiting for a large file to download.

Your file has the resource atom afterwards:

hexdump -C Glass50.mp4 | less

00000000 00 00 00 18 66 74 79 70 6d 70 34 32 01 1e 00 31 |....ftypmp42...1|
00000010 6d 70 34 32 69 73 6f 6d 02 5f 60 e9 6d 64 61 74 |mp42isom._`.mdat|

I posted some comments on this issue before and I repeat them here:

One way to confirm that your movie is really fast start is by issuing the following command on a MAC:

hexdump -C CatRED1.mov

00000000 00 00 00 20 66 74 79 70 71 74 20 20 20 05 03 00 |... ftypqt ...|
00000010 71 74 20 20 00 00 00 00 00 00 00 00 00 00 00 00 |qt ............|
00000020 00 00 00 08 77 69 64 65 01 b0 a6 05 6d 64 61 74 |....wide....mdat|
00000030 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................|

If you see that "mdat" before "moov" then your movie is not fast start. For a fast start movie you should see something like:

00000000 00 00 00 20 66 74 79 70 71 74 20 20 20 05 03 00 |... ftypqt ...|
00000010 71 74 20 20 00 00 00 00 00 00 00 00 00 00 00 00 |qt ............|
00000020 00 00 12 98 6d 6f 6f 76 00 00 00 6c 6d 76 68 64 |....moov...lmvhd|
00000030 00 00 00 00 c0 45 16 e2 c0 45 16 e3 00 00 0b b5 |.....E...E......|

where you would see the "moov" before "mdat".
 
I generated it as test for home use, and I didn't think about online use until later. But I'm impressed that you have a browser and internet connection that even has a chance of streaming a 50Mbps file!
 
I'm really surprised that my PC would not play that mp4 clip without stuttering and skipping frames. I have a fast dual-core chip, 4GBs of ram, and an 8800GTX. My PC normally will play any 1080p clip I throw at it.

Is a clip like that mainly relying on the processor or the graphics card?
 
I was trying for good quality so I used an unusually high bitrate (50 Mbps) which exceeds the Blu-Ray spec. Also it is 30 fps and pretty much all trailers are 24 fps I think. So both of those factors mean that clip will use more CPU / GPU power than is normal.

My own desktop PC doesn't have a hope of playing it smoothly at full res. I'd think your box would have the horsepower, so I wonder if your player software is taking full advantage of the GPU hardware for the H.264 decode. I think some players do, but most don't.
 
Tom said:
Is a clip like that mainly relying on the processor or the graphics card?
Click to expand...

I think one way to confirm if the graphics card is not involved is if you try to screen capture the window in Windows operating system that has the video playing. If the screen is green or black then its going through video overlay, etc., of the graphics card. If you are able to capture it okay then it is merely through processor. On Windows this behavior can be toggled.
 
Shaocaholica said:
Just because a video is using the graphics card hardware overlay, doesn't mean its actually accelerated or decoded by the GPU.
Click to expand...

Hi Shaocaholica, thanks for the update. I have limited knowledge in how different manufacturers implement solutions on GPU. Thanks for the correction.
 
jbeale said:
I was trying for good quality so I used an unusually high bitrate (50 Mbps) which exceeds the Blu-Ray spec. Also it is 30 fps and pretty much all trailers are 24 fps I think. So both of those factors mean that clip will use more CPU / GPU power than is normal.

My own desktop PC doesn't have a hope of playing it smoothly at full res. I'd think your box would have the horsepower, so I wonder if your player software is taking full advantage of the GPU hardware for the H.264 decode. I think some players do, but most don't.
Click to expand...

The bitrate alone breaks the accelerated decoding of most cards when it comes to MPEG-4 video. 40 Mbps for MPEG-4 is as high as many recent GPUs can handle without needing more power though the newest ones should be able to handle a little bit more because of their more advanced designs and additional silicon for more advanced hardware accelerated video decoding.
 
There can be VAST differences in encoders. If you're seeing problems with a 50mbit MPEG4 (which is a crazy high bitrate), then try another.

50mbit MPEG4 should be spotless.
 
jbeale said:
The only device I have that can play 1080p at 30 fps* in real time is a PS3. As a test, I tried rendering the same 6-second sequence in AVC (H.264) and MPEG2 format, both at 50 Mbps...
Click to expand...

I'm trying to find the good settings to output from Redcine to playable 1080P MP4 on PS3. ???
 
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